The invention relates to an induction furnace with a crucible having a crucible axis, an induction coil and a furnace body containing a gas-tight jacket, and also with a cover which can be placed on the furnace body and has at least one gas connection, a charging valve and a pouring apparatus, the furnace body and cover being joined together releasably but hermetically by a flange connection, and being journaled in the joined state in a furnace frame by a tilting mechanism which engages the cover, and after the flange connection is separated the furnace body can be removed from the cover which remains in the furnace frame.
An induction furnace of this kind, which is disclosed by German Patent 35 30 471 has the advantages that the cover serves as a reference platform which always remains in the furnace frame due to the bearings referred to, and all additional fittings, such as gas connections, the charging valve, the pouring system, and the measurement and observation devices can remain on the cover.
In the known system, however, only one coaxial pair of tilting bearings is present, whose common axis runs through the end of the pouring spout, so that, while pouring, transverse displacement of the overflow lip of the pouring spout will be minimized and the melt can also be poured off through a pouring tube surrounding the tilt axis. This arrangement, which is advantageous in itself, leads, however, to a comparatively high elevation of the only tilt axis above the floor, so that the induction furnace can also be brought into an opposite tilted position for the purpose of a slag removal operation without having the furnace body strike against the floor.
Through U.S. Pat. No. 3,350,083 it is known to arrange a single pair of tilt bearings such that the common tilt axis intersects the crucible axis at a right angle. This, however, has the consequence that the outlet opening of the pouring spout and the overflow edge of the slag removal lip move upon tilting in the corresponding direction on relatively long arcuate paths, so that not only an additionally provided pouring ladle but also a slag pot have to be suspended independently of one another on additional pivots in order to be able at all to perform a controlled pour or a controlled slag removal.
Through U.S. Pat. Nos. 3,311,361 and 3,486,745 it is known to provide induction furnaces with tilt bearings on both sides of the crucible axis, which are arranged each in the area of the pouring spout and the overflow edge of the slag removal trough and which are to be alternately unlocked according to whether a pouring of the metal or a slag removal is to be performed. Since in the case of a pouring or a slag removal operation a tilt bearing or pair of tilt bearings has to be brought out of engagement, the stability of the furnace mounting is imperiled unless an extremely heavy furnace frame with appropriate safety devices is acceptable.
The last-described furnace mountings, however, are always disposed on the furnace bottom, so that the advantages achieved by German Patent 35 30 471 have to be surrendered.